Showing posts with label Computers. Show all posts
Showing posts with label Computers. Show all posts

Sunday, March 3, 2013

Yes I have been neglecting my blog

It is true, I have been neglecting my blog. I have plans for brief reviews of ancient astronomy in the Book of Abraham, more posts about names in the Book of Mormon, and ancient rituals of conversion detailed in the Book of Mormon. But right now my time has been consumed with getting my code to work for my research. The other day I cleaned up two files that I had been working on for some time and I removed all the lines of code that I didn't need. All together I think I removed over 4,000 lines of code. It took me a few days to work through it and determine what I need and what I don't need.

In the meantime I uploaded a video of one of my simulations that I did as a proof of concept. I did this simulation to show my advisor that my fixes to the code are working and that more time should be devoted to the approach that I have been taking. He was impressed.



Here is the description that goes along with the video:

This is a short video that I made of a simulation that was done as a proof of concept. It shows a fractal distribution of density in the center of a star forming galaxy. This simulation is done using the MHD code Athena. The box size covers 1 kpc in each dimension and has a grid size of 128 in each dimension. The star forming region injects mass and energy into the center region of the simulation.

The proof of concept is for a flux fixer that allows the code to handle high kinetic energy situations where the total kinetic energy is a significant fraction of the total energy.

The visualization was done using Paraview.

Sunday, April 3, 2011

What does a computer virus look like?

This post is a general education post to help people become more familiar with computer viruses and trojans. For those who have never seen an actual computer virus taking over a computer, or who have seen it but did not realize what happened to their computer, here is a short video showing how a virus can take over your computer (I did not make this).



A couple of things to note here. The first warning sign that there was a virus was when the web page he was trying to access did not come up, but instead there was a page for a completely different site that came up. That should have been the first warning sign. The second was that a web page, not owned by Microsoft, said that there was something wrong with his computer. This would be like having some random person on the street come up to you and say that there has been a recalled issued for your car, and then they ask for your keys. You wouldn't give them your keys, so why would you trust some random website to tell you that your computer is broken and they need to fix it.

Up to this point the computer does not have a virus, it is just the webpage telling him that there is a problem. The next thing that was wrong with was that the web page began scanning his computer. No webpage, even legitimate ones should ever scan your computer. Again, that would be like someone calling you on the phone and offering to fix your car over the phone. If someone did that then you should suggest they take a trip to the loony bin, and when a website tries to do the same thing with your computer then you should also close your browser and don't go any further. Up to this point your computer still does not have a virus, and still works just fine. But when you download the virus, and run it (some viruses might be able to run immediately when you download them) then you have problems.

If you get to the point where you have a virus on your computer, then even if it says there are other problems, and even if it offers to fix the problem (for a fee) then don't do it. Either you will have to fix the problem yourself, if you know how, or find someone you can trust, who can fix it. Also keep in mind that no trustworthy anti-virus software will ever ask you to pay a fee after downloading it randomly off the internet. If you did not purchase the software in the normal way (off of a trusted site, or in an actual store) then it is not legitimate, and your should never give them credit card information.

Monday, December 22, 2008

A $93 Computer Reboot

Recently I had a problem with the automatic locks on my car, they just wouldn't work. So I checked all the fuses and everything I could think of, but to no avail. Because I was going into the local Honda dealer anyway to get a new key made I figured I would have them look at it. So I took it in and they hooked it up to their computer and the car's computer was not responding properly. So they reset the on board computer and that fixed the problem. In other words they just hit the reset button on the computer, and then they charged me $93 for it.

So I wondering how they did that and if there is anyway for me to reboot my car's computer without having to take it into the Honda dealer to have them hit the reset button and then charge me $93. It seems like a fairly simple process and I am only impeded in carrying out my own trouble-shooting due to my lack of computer interface and know how. If a high school drop out, grease monkey can figure it out I think I could figure it out.

Tuesday, December 16, 2008

Movement: Not as Simple as it Seems

I remember reading a short story many years ago by Issac Asimov (I think it was in his book I, Robot). In the story there is a robot named Robbie that plays with a child. While the robot can play ball and many other things the one thing that it cannot do is talk. Apparently Asimov thought that talking was such a complex thing that when we did get around to building robots, like Robbie, that we would have an immensely difficult time getting the robots to talk, whereas all the other normal human functions such as walking would be easy and natural to reproduce.

Thus for the most part, actions such as walking, picking things up and the like are almost always presented as simple for a robot and usually the first thing they "learn" how to do, whereas talking and language in general is presented as being the hard thing to deal with. This attitude towards the complexity of language and the simplicity of walking and moving was not particular to Asimov's stories. There are many more examples of this way of thinking, such as Data from Star Trek, Gort from The Day The Earth Stood Still, the Terminator and others. With these robots they have an easy time moving about but they have an immensely difficult time learning how to talk (or at least talking normally) and communicate.

There are a few notable exceptions to this, but this usually happens in movies where they actually try to make a robot as opposed to having a person wearing makeup (for example, Jonny 5 from Short Circuit). In these cases the actual logistics of making a robot become apparent and the "simple" things such as walking and picking things up are no longer so simple, while the other thing, language, which authors and philosophers considered so difficult can easily be reproduced.

Lately there have been real attempts to make functioning robots, like they have in movies, and while scientists have been able to make computers talk and respond to speech for years, they are having an immensely difficult time with something so simple as walking. Even with all the combined brain power of a corporation like Honda the best they can do is to get a robot to walk up an incline (with the incline already programmed into the robot). Other groups at universities that are developing robots are running into similar problems, they can make them talk, but when it comes to moving and picking things up then it becomes much more difficult.

So it is ironic that authors and philosophers would consider language an extremely complex thing and difficult, if not impossible, for robots to master ends up being one of the easier things. This mistake is understandable because as we learn and grow we first learn to move and to walk and then we learn how to talk. While we learn how to walk fairly quickly, it takes us years to learn how to use language. Granted computers cannot use language to our level, but they can reproduce language in a fairly believable format, while they have difficulty with the simple things like walking.

I guess the reason why I am pointing this out is that I am amused by the fact that many people egotistically think that their words are so hard and complex to understand that surely a robot would have immense difficulty reproducing them, and for robots that is what they must struggle with the most, because that is what we struggle with the most. But when it comes down to it, our language is comparatively simple and it is everything else that is complex. Perhaps the complexity and problems of language are self-created and our inability to learn it does not come from our lack of intelligence, but our lack of intelligibility.

Thursday, October 2, 2008

Mailbox Not Found

I recently got an email from a listserv that I am signed on with which read:

"You have been automatically removed from the PTFAVE list (PHYSICS TODAY FAVORITES) as a result of repeated delivery error reports from your mail system.

While you are obviously able to receive mail, your mail system has been regularly reporting to the PTFAVE list that your account did not exist"

and finally:

"- The last reported error was: 5.1.1 550 Mailbox not found"

Now what is odd about this is that I know that this account is disabled (hence the error message) but somehow I got the message. I had originally set up the now disabled account to forward to another account and it has been doing that, until the account was disabled several months ago. But apparently I can still get mail from it.

But wait there's more! I wanted to see if the account was still working so I sent an email to myself thinking that if it got forwarded then the account was still active and if it did not then it wasn't. So I tried and this is what I got:

" ----- The following addresses had permanent fatal errors -----
#####@###.###.edu
(reason: 550 Mailbox not found)
(expanded from: #####@###.edu)

----- Transcript of session follows -----
... while talking to #####.###.edu.:
>>> DATA
<<< 550 Mailbox not found
#####@###.edu... User unknown
X-Actual-Recipient: RFC822; #####@###.###.edu
Action: failed
Status: 5.1.1
Remote-MTA: DNS; #####.###.edu
Diagnostic-Code: SMTP; 550 Mailbox not found
Last-Attempt-Date: Thu, 25 Sep 2008 09:17:59 -0600
#####@###.edu"

So my mailbox doesn't exist and it won't forward an email I send to it but gives me an error message instead, BUT I'M STILL GETTING MAIL FROM IT! Try and figure that one out.